HeadTexture#of prints a stacktrace

[Lemar98]

There is one problem that worries me. Although you may say that this is not a problem.

If information about a player whose skin is not on the mojang servers is passed to the HeadTexture#of function, then this function will print an error to the console.

My suggestion is to either make a callback to handle the error, or make a throw function.

If you want I can do PR ;)